Near-eye-display with rapid spherical image scanning

ABSTRACT

A near-eye display that employs rapid spherical image scanning using liquid crystal retarder with concentric imaging and optical elements comprising a display with spherically curved concave image surface topped with polarizer; a spherically curved liquid crystal retarder composite reflector having a see-thru mirror topped at the concave side with electronically controlled liquid crystal retarder strips; a see-thru spherically curved mirror-polarizer composite with mirror at the convex side and polarizer at the concave side; a frame to support, protect the device, and mount the device to the head.

PRIORITY

This application is a continuation of co-pending application Ser. No.16/201,072 filed Nov. 27, 2018 which is a continuation-in-part of U.S.patent application Ser. No. 15/708,135, filed Sep. 19, 2017 (now U.S.Ser. No. 10/310,273 issued Jun. 4, 2019) by the same inventor, which inturn claims the benefit of provisional patent application PPA #62396778filed Sep. 19, 2016.

BACKGROUND

Some near eye displays (NEDs) are used in virtual reality (VR) devices.NEDs of VR devices have eyes enclosed from external view to effectimmersive display. VR devices are optimal with minimum of 80 degreesfield-of-view (FOV) so that the viewer does not seem to be looking outfrom the window with the edges of the view showing. NEDs in VR devicesuse combination of lenses to focus on small display or image source. Theproblem is that this train of lenses are uncomfortably long, complex andbulky to achieve the minimum FOV and large eye box. An eye has a FOV ofaround 200 degrees horizontal and around 135 degrees vertical with eyerotation included (no head movement relative to NED). The pupil of theeye can be in locations covering around ¾ of an inch cube eye box witheye rotation and being slightly far or near the NED.

NEDs having wide FOV and large eye box approaching these extents areideal. Unfortunately, even the largest lens in NEDs that can be used inVR devices prohibits the NED from achieving a very wide FOV. Opticalproblems arise when the eye starts to rotate from the optical axis ormove away from the focal plane. Attempts to solve these problems usingconcentric optical system did not produce satisfactory FOV or imagequality. Prior concentric optical system for NEDs use combination ofsee-thru mirrors, polarizers, quarterwave retarders, and lens system tocut and fold the optical path. Unfortunately, light from the imagesource passes through and reflected from these elements so many timesthat the image quality becomes degraded so much.

There are NEDs used for see-thru or augmented reality (AR) devices. ARNEDs are similar to VR NEDs except AR NEDs can overlay the image to theexternal view. NEDs in AR devices have displays or image sources placedaway from line of sight and use angled see-thru mirror or beam splitterto see the local display overlaid to the external view. These AR NEDshave an unsatisfactory FOV because the angled see-thru mirror prohibitsthe NED from having wide FOV. Prior concentric optical system for NEDsof AR devices have failed to produce wide FOV with good image quality.

NEDs in AR devices have an image from a local display overlaid againstthe external view. Dark parts of the image unfortunately turn light whenset against bright external view. The image could be very hard to seeagainst brightly colored external view. Masking or occluding systems tocover parts or the whole image of the local display from external viewto control the opacity against the external view have been tried.Unfortunately, these attempts have met limited success.

In view of the foregoing, improvements to NEDs are wanted by theindustry.

SUMMARY

Enclosed herein is, in one embodiment, a NED that employs rapidspherical image scanning using spherical liquid crystal retardercomposite reflector with a display having a spherically curved concaveimage surface topped with polarizer. This may include a sphericallycurved concave composite reflector having see-thru concave mirror on theconvex side and strips of electronically controlled liquid crystalretarder on the concave side, a spherically curved mirror-polarizercomposite reflector with see-thru mirror at the convex side andpolarizer at the concave side. These embodiments may have a frame tosupport, protect, and mount the device to a user's head. There areseveral advantages to the present disclosure such as:

-   -   Providing a NED that employs rapid spherical image scanning that        produces “persistence of vision” to realize a wider FOV and        larger eye box    -   a folded optical path that makes the NED compact and still have        satisfactory clearer view of the display    -   Providing a bigger space between the eye and the NED,    -   The ability for integrating a spherical digital imaging system        with high resolution and wide FOV with occluding support.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagrammatic isometric illustration for the paths of lightfrom display point source to finally reaching an eye.

FIG. 2A is a graphic illustration useful in explaining spherical imagescanning.

FIG. 2B is a graphic illustration useful in explaining spherical imagescanning.

FIG. 3A shows isometric rear view of the NED.

FIG. 3B shows top view of the NED.

FIG. 3C shows Section A-A view from FIG. 3D.

FIG. 3D shows rear view of the NED.

FIG. 4 shows cut-away plan view of the NED.

FIG. 5 is a diagrammatic isometric illustration of the spherical digitalphotographic system or external viewing system.

FIG. 6A shows rear isometric view of the NED with spherical digitalphotographic system.

FIG. 6B shows top view of the NED with spherical digital photographicsystem.

FIG. 6C shows Section A-A view from FIG. 6D of the NED with sphericaldigital photographic system.

FIG. 6D shows rear view of the NED with spherical digital photographicsystem.

FIG. 7 shows cut-away plan view of the NED with spherical digitalphotographic system.

FIG. 8 shows cut-away plan view of a NED scaled larger to be used asbi-ocular viewing device.

FIG. 9 shows cut-away plan view of the NED of the current applicationwith spherical digital imaging system using liquid crystal retarderscaled larger to be used as bi-ocular viewing device.

FIG. 10 shows cut-away plan view of the NED applicable the currentapplication scaled larger and configured to 360 degrees as bi-ocularviewing device.

FIG. 11 shows spherical digital photographic system with compositeconcave reflector with full mirrors as alternative to the plain see-thruconcave reflector.

FIG. 12 shows cut-away plan view of the spherical digital photographicsystem applicable for the current application configured to 360 degrees.

FIG. 13 shows cut away plan view of another embodiment of the sphericaldigital photographic system or external viewing system.

DESCRIPTION Generality of Invention

This application should be read in the most general possible form. Thisincludes, without limitation, the following:

References to specific techniques include alternative and more generaltechniques, especially when discussing aspects of the invention, or howthe invention might be made or used.

References to “preferred” techniques generally mean that the inventorscontemplate using those techniques, and think they are best for theintended application. This does not exclude other techniques for theinvention and does not mean that those techniques are necessarilyessential or would be preferred in all circumstances.

References to contemplated causes and effects for some implementationsdo not preclude other causes or effects that might occur in otherimplementations.

References to reasons for using particular techniques do not precludeother reasons or techniques, even if completely contrary, wherecircumstances would indicate that the stated reasons or techniques arenot as applicable.

Furthermore, the invention is in no way limited to the specifics of anyparticular embodiments and examples disclosed herein. Many othervariations are possible which remain within the content, scope andspirit of the invention, and these variations would become clear tothose skilled in the art after perusal of this application.

Lexicography

The terms “effect”, “with the effect of” (and similar terms and phrases)generally indicate any consequence, whether assured, probable, or merelypossible, of a stated arrangement, cause, method, or technique, withoutany implication that an effect or a connection between cause and effectare intentional or purposive.

The term “relatively” (and similar terms and phrases) generallyindicates any relationship in which a comparison is possible, includingwithout limitation “relatively less”, “relatively more”, and the like.In the context of the invention, where a measure or value is indicatedto have a relationship “relatively”, that relationship need not beprecise, need not be well-defined, need not be by comparison with anyparticular or specific other measure or value. For example, and withoutlimitation, in cases in which a measure or value is “relativelyincreased” or “relatively more”, that comparison need not be withrespect to any known measure or value but might be with respect to ameasure or value held by that measurement or value at another place ortime.

The term “substantially” (and similar terms and phrases) generallyindicates any case or circumstance in which a determination, measure,value, or otherwise, is equal, equivalent, nearly equal, nearlyequivalent, or approximately, what the measure or value is recited. Theterms “substantially all” and “substantially none” (and similar termsand phrases) generally indicate any case or circumstance in which allbut a relatively minor amount or number (for “substantially all”) ornone but a relatively minor amount or number (for “substantially none”)have the stated property. The terms “substantial effect” (and similarterms and phrases) generally indicate any case or circumstance in whichan effect might be detected or determined.

The terms “this application”, “this disclosure” (and similar terms andphrases) generally indicate any material shown or suggested by anyportions of this application, individually or collectively, and includeall reasonable conclusions that might be drawn by those skilled in theart when this application is reviewed, even if those conclusions wouldnot have been apparent at the time this application is originally filed.

DETAILED DESCRIPTION

Specific examples of components and arrangements are described below tosimplify the present disclosure. These are, of course, merely examplesand are not intended to be limiting. In addition, the present disclosuremay repeat reference numerals and/or letters in the various examples.This repetition is for the purpose of simplicity and clarity and doesnot in itself dictate a relationship between the various embodimentsand/or configurations discussed.

FIGS. 1 to 4

FIGS. 1 to 5 shows an NED that employs rapid spherical image scanningusing liquid crystal retarder composite reflector has a sphericallycurved polarized concave display 110 like spherically curved LCDdisplays. The display or image source can be see-thru for heads-upapplications or opaque for VR applications. Alternatively, the displaycan be composed of spherically curved non-polarized concave display 110Alike spherically curved OLED displays with the image showing at theconcave side and topped by display polarizer 110B. Typical setup of thedisplay is that it is controlled by the display controller electronicsor circuits (120 of FIG. 4) and computer. The display polarizer 110B isassumed to have longitudinal polarizing orientation 110B′ although otherorientation will suffice. Concentrically at the concave side of thedisplay polarizer (110B) is the spherically curved composite reflector(112). The composite reflector (112) is composed of sphericaltransparent base topped with see-thru concave mirror (112A) at theconvex side and topped at the concave side by electronically controlledliquid crystal retarder strips (112B) which are alternately switched-on(ON) to become quarterwave retarders with the slow axis (S′) oriented ataround 45 degrees from polarizing orientation (110B′) of displaypolarizer (110B) and fast axis (F′) oriented at 90 degrees from the slowaxis (S′) and switched-off (OFF) to remain transparent by the controllerelectronics or circuits (118 FIG. 4).

Concentrically at the concave side of the composite reflector (112) isthe see-thru convex mirror/polarizer (114). It is composed of sphericaltransparent base, topped with see-thru convex mirror (114A) at theconvex side and topped at the concave side by exit polarizer (114B). Theexit polarizer has latitudinal polarizing orientation (114B′) ororiented at around 90 degrees from display polarizing orientation(110B′). The NED of current application is supported and mounted to thehead by the frame and support (116 FIG. 4). The NED of currentapplication can be see-thru for heads-up application or enclosed for VRapplication.

Operation First Embodiment

The spherically curved concave display (110A) is the image source of theNED of current application. Light from a point on the display (1) ispolarized by the display polarizer (110B). Let us assume that thedisplay polarizer is set to polarize light to vertical orientation(110B′). When non-polarized light (3) from the light source (1) istransmitted by the polarizer (110B), light becomes vertically polarized(5). The polarized light (5) from the display (110) reaches thecomposite liquid crystal retarder reflector (112). Upon reaching thesee-thru concave mirror (112A) about half of the polarized light (5) isreflected to fade and about half is transmitted. The transmittedpolarized light (5) then encounters the transparent switched-off (OFF)liquid crystal retarder strip (112B) and then transmitted. Thetransmitted polarized light (5) reaches the composite convex reflector(114). Upon reaching the see-thru convex mirror (114A) about half isreflected (9) and about half is transmitted (7). The transmitted lightwhich is vertically polarized (9) is blocked by the polarizer (114B)which is oriented 90 degrees from display polarizer (110B). Thereflected polarized light (9) reaches the switched-on (ON) liquidcrystal retarder which is actively a quarterwave retarder. The linearlypolarized light (9) is transmitted as circularly right or circularlyleft polarized light (11). The circularly polarized light (11) reachesthe see-thru concave mirror (112A). Half of the light is reflected incircularly opposite direction (13). The circularly polarized light (13)then reaches the switched-on (ON) liquid crystal retarder (112B) andtransmits the circularly polarized light as horizontally orientedlinearly polarized light (15). The horizontally polarized light (15)then reaches the see-thru convex mirror (114A) again. About half of thehorizontally polarized light (17) is transmitted and reaches thepolarizer (114B). This time, the horizontally polarized light istransmitted (19) from the polarizer (114B) and reaches the eye.

In operation the “A” parts of the display (110 FIG. 2A) reaches the eye.The liquid crystal retarder strips that are switched-on (ON) areswitched OFF and the switched-off strips (OFF) are switched ON. Thistime, the “B” parts of the display (110 FIG. 2B) reaches the eye. Thishappens so fast that complete pictures are perceived by the viewer. Whensee-thru display is used, the image is overlaid to external view.

Alternative Embodiments

One alternative embodiment is similar to the first embodiment except thedisplay or image source (110A) is replaced by cylindrically curved orflexible display. The fiber-optic faceplate (128) is topped at thecylindrically curved side by the display (102A) and topped atspherically curved concave side by the display polarizer (102B). Yetanother embodiment may be used in VR applications. In an alternativeembodiment the image source is from a cylindrically curved or flexibledisplay (110A) and the image is relayed to the spherically curvedconcave side of the fiber-optic faceplate (128). Still anotherembodiment is one that it is not enclosed and uses see-thru display orthat the display is topped at the convex side with LCD occluder orelectronic mask.

FIGS. 1 to 7

These figures show a spherical photographic system (122, 124, and 126),which is the source of external image data that is processed and mergedwith local image data to feed the spherical display (110) working asexternal viewing system, is added on the convex side of the opaquespherical display (110). The external viewing system has spherical imagesensor (126B). The image sensor is made up photosensors that convertslight into digital images for image processing and viewing. The imagephotosensor is topped at the convex side with polarizer (126A). Thepolarizer (126A) is assumed to have horizontal polarizing orientation(126A′). Close to the convex side of the spherical image photosensorwith polarizer is the spherical composite reflector (124). The sphericalcomposite reflector (124) is composed of transparent base with strips ofretroreflective mirrors (124A), full mirrors (124B), and clear base(124C). The spherical composite reflector is mounted on cranks withmotor (130) which is a spherically and circularly moving device. About ⅓the radius of photosensor distance at the convex side of the compositereflector is the composite spherical composite see-thru reflector (122).The spherical composite see-thru reflector (122) is composed of aspherical clear base topped at the concave side with see-thru mirror(122B) and topped at the convex side with polarizer (122A). Thepolarizer is assumed to have vertical polarizing orientation (122A′).

Operation

The first part of the operation is capturing the external view using theexternal viewing system. An unpolarized light ray (1) coming fromexternal point (19) reaches the polarizer (122A) of the sphericalcomposite see-thru reflector (122). The light is vertically polarized(3) then reaches the see-thru mirror (122B). About half of the light isreflected and the rest is transmitted (5). The transmitted light (5) isreflected by the retroreflector (124A, 7) to its origin at the see-thruconcave mirror (122B). The retroreflected light (7) is elliptically orcircularly polarized. About half of the light is transmitted out and therest is reflected in (9). The reflected light (9) is circularlypolarized at the opposite direction. Geometrically, the reflected light(9) should hit the full mirror (124B). The full mirror (124B) reflectsthe light (11) to the concave mirror (122B). About half of the light istransmitted out and the rest is reflected in (13). Geometrically, thereflected light should hit the clear base (124C) and transmitted (15).The transmitted light reaches and passes through the polarizer (126A)because the light (15) is circularly polarized. The light (17) isvertically polarized and finally reaches the image sensor (126B) andconverted to digital image information by the electronics or circuitsand computer. Strips or partial digital image is captured.

The cranks and motor assembly (130) when powered moves the compositereflector spherically and circularly along with counter balance (notshown) to prevent or minimize vibration. The clear strips on thecomposite reflector moves as scanning strips thereby completing thedigital image captured. The scanning is so fast that suitable numbers ofimages are captured for video display. The captured external digitalimages are fed to the display for external viewing or merged with thedisplay digital images for combined display. A three-dimensional digitalmap data of the scene can be used to implement or control occludingapplications on both the external digital images and display digitalimages for augmented reality viewing. External light rays notretroreflected that passes through the clear base (124C) are verticallypolarized and are blocked by the image sensor polarizer (126A).

FIGS. 1 to 7 and 20

These figures show embodiments where the spherical concave display isreplaced by cylindrical or flexible display topped at the concave sidewith fiberoptic faceplate with spherically concave image surface. Theimage from the cylindrical display is relayed by the fiberopticfaceplate to the spherical concave surface.

In yet other embodiments, the spherical image sensor (126B) is replacedby cylindrical or flexible image sensor (142) that is topped at theconvex side with fiberoptic faceplate with spherically convex surface(134). The convex surface of the fiberoptic faceplate is topped withpolarizer (126A).

The operation is similar to previously described embodiments, exceptthat the external image light that passes the polarizer (126A) isrelayed by the fiberoptic faceplate to the cylindrical image photosensor(126B).

FIGS. 8 to 10

Here, the display is large enough for bi-ocular viewing application. Theembodiment can also cover 360 degrees of field of view. With 360 degreesconfiguration, cranks are not used and the spherical composite reflector(124) is driven circularly over the spherical image sensor (126). Thisthereby gives all the advantages of bi-ocular viewing. The image isviewed from both left and right eyes. The image is like viewed beyondthe screen producing bi-ocular viewing experience.

FIG. 11

In this embodiment full mirrors are added on the spherical compositesee-thru reflector (122). Here, 75% of image light is reflected by fullmirrors at the composite see-thru reflector (122) before passing throughthe clear bases at the composite reflector (124).

FIG. 12

In this embodiment, the external viewing device is used as a sphericalimage capturing device or camera. The embodiment can be configured up to360 degrees of image capture. With 360 degrees of image capture, cranksare not used and the spherical composite reflector is driven circularlyabout the concentric center (21) over the spherical image photosensor(128). The image data is video streamed or stored in data storage devicefor printing and display purposes.

FIG. 13

In this embodiment the composite reflector (124) is replaced by areflector with strips of clear base (124C) and retroreflective mirrors(124A). The other difference is that the radius of the externalreflector (122) is approximately 2 times the radius of the photosensor(126) so that geometric reflections of light hits the clear base (124C)and focused on photosensor surface. The embodiment can also replaceexternal the viewing system of fourth and fifth embodiments. Theembodiment can also be configured up to 360 degrees of image capture.

Here, after light is retroreflected (124A) and reflected by see-thrucomposite reflector (122), it geometrically hits the clear base thenreaches the spherical image photosensor (128) thereby reducing lightbending.

Advantages

From the descriptions provided herein, a number of advantages of thisdisclosure become evident:

-   -   a) Fewer elements along the path of light from external view to        the eye and fewer optical folding have been used to realize        clearer view of the NED display.    -   b) Concave surface of the composite convex reflector (114, 114B)        provided bigger space between the eye and NED to accommodate        eyeglasses and other devices.    -   c) The shape of the NED concentric optical system can be more        freely designed for aesthetic look.    -   d) The more than 180 field of view can be accommodated.    -   e) Occluding system which allows the external view and local        display to be both controlled and merged into one can be fully        realized.    -   f) The composite scanning reflector of patent application Ser.        No. 15/708,135 is replaced by non-moving scanning composite        reflector.    -   g) Moving bodies at the scene are captured instantly at their        location even for 360 degrees image capturing applications.

In view of the foregoing, the reader will see that the near eye displaydevice that employs rapid spherical image scanning using liquid crystalretarder of the various embodiments can be used as for various AR and VRapplications that requires bigger FOVs than currently available, that islightweight, and conveniently not bulky. In addition, the near eyedisplay of current disclosure can be shaped aesthetically withnegligibly or without compromising the balanced movement of parts. Thenear eye display of current application can also be made without movingparts.

Although the description above contains many specificities, these shouldnot be construed as limiting the scope of the embodiments but as merelyproviding illustrations of some of several embodiments. For example, andwithout limitation, longitudinal polarizing orientation of the opticalsystem can be oriented to different angle; other combinations of theembodiments can be used to satisfy user requirements; other sphericallyand circularly restraining device can be used to guide the sphericallymoving parts; other mechanical device or means to drive the moving partsspherically and circularly that achieves balancing can be used; othertypes of motors can be used to drive the cranks; slave cranks can beattached to a motor and be driving cranks as well; the counterbalancecan be any number and in any shape like for example a ring shape or madeup of any material as long as it counterbalances to reduce thevibrations to negligible or none; other choice of FOV can be used; thiscan be bi-ocular (single) or binocular (in pair); other display thatproduces spherically concave image can be used; other angles betweencrank shaft and crank arms can be used as long as all cranks arms haveidentical angles from crank shaft; the cylindrically curved display canbe elliptically curved or free-form curved display. The composite liquidcrystal strips can be also transparently set every third strip or more.

The above illustration provides many different embodiments orembodiments for implementing different features of the invention.Specific embodiments of components and processes are described to helpclarify the invention. These are, of course, merely embodiments and arenot intended to limit the invention from that described in the claims.

Although the invention is illustrated and described herein as embodiedin one or more specific examples, it is nevertheless not intended to belimited to the details shown, since various modifications and structuralchanges may be made therein without departing from the spirit of theinvention and within the scope and range of equivalents of the claims.Accordingly, it is appropriate that the appended claims be construedbroadly and, in a manner, consistent with the scope of the invention, asset forth in the following claims.

I claim:
 1. A near eye display device comprising: a frame withconcentric imaging and optical elements with said imaging element havinga spherically curved concave image surface topped with a polarizer; aspherically curved composite reflector, said reflector including aplurality of strips of liquid crystal retarders, said strips coupled toa controller circuit; wherein said controller circuit is operable tomodulate the optical transparency of the composite reflector byalternatively switching the polarization of a first portion of the slitsto a first polarization while switching a second portion of the slits toa second polarization.
 2. The device of claim 1 wherein the displaydevice further includes an LCD occluder disposed on the convex side,said occluder coupled to a second controller circuit.
 3. The device ofclaim 1 wherein the said display device includes a fiber-optic faceplateon the concave side wherein the concave surface of the fiber-opticfaceplate is topped with a polarizer.
 4. A method for a near eye displaydevice including: electrically coupling a first plurality of liquidcrystal retarders to a controller; electrically coupling a secondplurality of liquid crystal retarders to the controller; physicallycoupling the liquid crystal retarders to a see-thru mirror and apolarizer, and alternating the optical density of the first plurality ofliquid crystal retarders and the second plurality of liquid crystalretarders by varying the polarity of each plurality of liquid crystalretarders.
 5. The method of claim 4 further including: an opticaloccluder disposed in optical alignment with the first and secondplurality of liquid crystal retarders.
 6. The method of claim 4 whereinthe see-thru mirror and polarizer are in part, spherically concave. 7.The method of claim 7 wherein the near eye display device includes animage source, said image source disposed in optical alignment with thefirst and second liquid crystal occluders.